Cutting edge for work machine, blade for work machine, and work machine

ABSTRACT

A cutting edge has an attachment portion and a wear portion. The attachment portion has a first thickness, which is a maximum value of a thickness between a first surface and a second surface. The wear portion includes a first portion having a third surface contiguous to the first surface and a fourth surface facing away from the third surface, and having a second thickness between the third surface and the fourth surface and smaller than the first thickness, and an edge located opposite to the attachment portion. The second portion extends on the first portion from a portion of the fourth surface toward a side opposite to the third surface, and also extends on the first portion from the edge toward the attachment portion.

TECHNICAL FIELD

The present disclosure relates to a cutting edge for a work machine, a blade for a work machine, and a work machine.

BACKGROUND ART

There is a demand for work machines such as a motor grader to work more efficiently. Working more efficiently includes better performance for excavation, a cutting edge enhanced in durability, and the like. A cutting edge that addresses this issue is disclosed for example in U.S. Pat. No. 3,021,626 (PTL 1).

The cutting edge disclosed in PTL 1 has a front surface with a raised portion and a rear surface with a reinforcing rib.

CITATION LIST Patent Literature

PTL 1: U.S. Pat. No. 3,021,626

SUMMARY OF INVENTION Technical Problem

The cutting edge disclosed in PTL 1, however, has an edge with low rigidity and is thus difficult to be enhanced in durability.

An object of the present disclosure is to provide a cutting edge for a work machine, a blade for a work machine, and a work machine, that can provide satisfactory performance for excavation and be easily improved in durability.

Solution to Problem

The presently disclosed cutting edge for a work machine is a cutting edge for a work machine attached to the work machine, and including an attachment portion and a wear portion. The attachment portion has a first surface and a second surface facing away from each other, and a first thickness being a maximum value of a thickness between the first surface and the second surface. The wear portion is integrated with the attachment portion. The wear portion has a first portion and a second portion. The first portion has a third surface continuous to the first surface and a fourth surface facing away from the third surface, and has a second thickness between the third surface and the fourth surface, and an edge located opposite to the attachment portion. The second thickness is smaller than the first thickness. The second portion extends from a portion of the fourth surface of the first portion toward a side opposite to the third surface, and extends from the edge of the first portion toward the attachment portion.

Advantageous Effects of Invention

According to the present disclosure, a cutting edge for a work machine, a blade for a work machine, and a work machine, that provides satisfactory performance for excavation and is easily improved in durability can be implemented.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective view showing a configuration of a motor grader as a work machine according to a first embodiment.

FIG. 2 is a side view showing a configuration of a blade for a work machine included in the work machine shown in FIG. 1.

FIG. 3 is a front perspective view of a cutting edge included in the FIG. 2 blade for the work machine.

FIG. 4 is a rear perspective view of the cutting edge included in the FIG. 2 blade for the work machine.

FIG. 5 is a cross section taken along a line V-V indicated in FIG. 4.

FIG. 6 is a cross section taken along a line VI-VI indicated in FIG. 5.

FIG. 7 is a front, partial perspective view of a configuration of a cutting edge included in a work machine according to a second embodiment.

FIG. 8 is a rear, partial perspective view of the configuration of the cutting edge included in the work machine according to the second embodiment.

FIG. 9 is a cross section taken along a line IX-IX indicated in FIG. 8.

FIG. 10 is a cross section taken along a line X-X indicated in FIG. 8.

DESCRIPTION OF EMBODIMENTS

Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In the specification and drawings, identical or corresponding components are identically denoted and will not be described redundantly. In the drawings, configuration may be omitted or simplified for convenience of description. Each embodiment and each variation may at least partially be combined together.

First Embodiment Configuration of Work Machine

Initially, a configuration of a motor grader which is an example of a work machine to which the concept of the present disclosure is applicable, will be described. Note that the present disclosure is also applicable to other work machines than the motor grader having a blade.

FIG. 1 is a perspective view schematically showing a configuration of a motor grader according to a first embodiment. As shown in FIG. 1, a motor grader 10 according to the present embodiment mainly includes a work implement 1, a body frame 2, a cab (or driver's compartment) 3, and traveling wheels 4 and 5. Motor grader 10 includes components such as an engine disposed in an engine compartment 2 aa. Work implement 1 for example includes a blade 11. Motor grader 10 can perform operations such as a land grading operation, a snow plowing operation, a light cutting operation, and a material mixing operation by blade 11.

In the following description for the drawings, a direction in which motor grader 10 travels straight forward/backward is referred to as a forward/backward direction of motor grader 10. In the forward/backward direction of motor grader 10, a side on which front wheel 4 is located with respect to work implement 1 is defined as a forward direction. In the forward/backward direction of motor grader 10, a side on which rear wheel 5 is located with respect to work implement 1 is defined as a backward direction. A rightward/leftward direction of motor grader 10 is a direction orthogonal to the forward/backward direction in a plan view. When looking in the forward direction, a right side and a left side in the rightward/leftward direction are a rightward direction and a rightward direction, respectively. An upward/downward direction of motor grader 10 is a direction orthogonal to a plane defined by the forward/backward direction and the rightward/leftward direction. In the upward/downward direction, a side on which the ground is present is a downward side, and a side on which the sky is present is an upward side.

Body frame 2 includes a rear frame 2 a and a front frame 2 b. Rear frame 2 a supports an exterior cover 2 ab and components such as the engine disposed in engine compartment 2 aa. Exterior cover 2 ab covers engine compartment 2 aa. For example, four rear wheels 5 are attached to rear frame 2 a. Four rear wheels 5 can each be rotatably driven by a driving force received from the engine.

Front frame 2 b has a base end portion coupled to rear frame 2 a and a foremost end portion opposite to the base end portion. Front frame 2 b has the base end portion coupled to a foremost end portion of rear frame 2 a by a center pin extending in the upward/downward direction.

An articulation cylinder (not shown) is attached between front frame 2 b and rear frame 2 a. Front frame 2 b is provided articulatably with respect to rear frame 2 a as an articulation cylinder extends and retracts.

Front frame 2 b has its foremost end portion for example with two front wheels 4 rotatably attached thereto. Front wheel 4 is attached to front frame 2 b pivotably as a steering cylinder 6 extends and retracts. Motor grader 10 can change in which direction it proceeds by extending and retracting steering cylinder 6.

Cab 3 is mounted on front frame 2 b. Inside cab 3 is provided an operation unit (not shown) such as a handle, a transmission lever, a lever operated to control work implement 1, a brake, an accelerator pedal, and an inching pedal, etc. Cab 3 may be mounted on rear frame 2 a.

Work implement 1 mainly includes, for example, blade 11, a drawbar 12, a circle 13, lift cylinders 14 and 15, a drawbar shift cylinder 16, a blade shift cylinder 17, and a hydraulic motor 18.

Drawbar 12 is disposed below front frame 2 b. Drawbar 12 has a front end portion coupled with the foremost end portion of front frame 2 b via a ball bearing. Drawbar 12 has the front end portion attached to the foremost end portion of front frame 2 b so as to be capable of swinging.

Drawbar 12 has a rear end portion supported by front frame 2 b via a pair of lift cylinders 14 and 15. As the pair of lift cylinders 14 and 15 extends and retracts, drawbar 12 can have the rear end portion moved upward/downward with respect to front frame 2 b. Further, as the paired lift cylinders 14 and 15 differently extend and retract, drawbar 12 can swing about an axis extending in the forward/backward direction.

Circle 13 is disposed below drawbar 12. Circle 13 is pivotably (rotatably) attached to the rear end portion of drawbar 12. Circle 13 can be driven by hydraulic motor 18 to pivot both clockwise and counterclockwise with respect to drawbar 12, as seen above work machine 10.

Blade 11 is supported by circle 13. As circle 13 is driven to rotate, blade 11 has a blade angle adjusted. The blade angle is a tilt angle of blade 11 with respect to the forward/backward direction of motor grader 10, as seen at a point above work machine 10 (in plan view).

Blade 11 is disposed between front wheel 4 and rear wheel 5. Blade shift cylinder 17 is attached to circle 13 and blade 11 and is disposed longitudinally of blade 11. Blade 11 is movable by blade shift cylinder 17 in the rightward/leftward direction with respect to circle 13.

A tilt cylinder (not shown) is attached to circle 13 and blade 11. As the tilt cylinder extends and retracts, blade 11 can swing with respect to circle 13 about an axis extending longitudinally of blade 11 to have a tilt angle changed with respect to a direction in which blade 11 proceeds.

Blade 11 is thus attached to the body of the work machine composed of traveling wheels 4 and 5, body frame 2, and cab 3. Blade 11 is configured to be capable, via drawbar 12 and circle 13, of: moving up and down with respect to the body of the work machine; swinging about an axis extending in a direction in which work machine 10 proceeds; changing a tilt angle with respect to the forward/backward direction; moving in the rightward/leftward direction; and swinging about an axis extending longitudinally of blade 11.

Configuration of Blade 11

Hereinafter, a configuration of blade 11 included in work machine 10 (a blade for a work machine) will be described with reference to FIG. 2.

FIG. 2 is a side view showing a configuration of a blade for a work machine included in the work machine shown in FIG. 1. As shown in FIG. 2, blade 11 has a blade body 11 a and a cutting edge 20. Blade body 11 a has a front surface 11 aa and a rear surface 11 ab facing away from each other. Blade body 11 a has front surface 11 as and rear surface 11 ab each curved in a cross section of blade body 11 a taken vertically (or in a direction along a shorter side of blade 11).

Blade body 11 a has rear surface flab with a pair of rails 11 d attached thereto via a holding frame 11 e. The pair of rails 11 d is supported by a guide bracket (not shown) slidably along blade 11. Blade 11 is attached to the body of the work machine via a blade supporting mechanism (not shown) including the guide bracket.

Blade body 11 a has a lower end portion to which cutting edge 20 is attached. Cutting edge 20 is fixed to blade body 11 a for example with a bolt 11 b and a nut 11 c. Specifically, bolt 11 b is inserted from a front side into a through hole 20 h of cutting edge 20 and a through hole 11 f of blade body 11 a, and fastened by nut 11 c behind blade body 11 a. Cutting edge 20 is thus fixed to blade body 11 a.

Configuration of Cutting Edge 20

Hereinafter, a configuration of cutting edge 20 included in blade 11 will be described with reference to FIGS. 3 to 6.

FIGS. 3 and 4 are a front perspective view and a rear perspective view, respectively, of a configuration of a cutting edge included in the FIG. 2 blade for the work machine. FIGS. 5 and 6 are a cross section taken along a line V-V indicated in FIG. 4 and a cross section taken along a line VI-VI indicated in FIG. 5, respectively.

As shown in FIG. 5, cutting edge 20 has an attachment portion 21, a wear portion 22, and an intermediate portion 23. Attachment portion 21, wear portion 22 and intermediate portion 23 are integrated together.

Attachment portion 21 has a first surface 20A and a second surface 20B facing away from each other. First surface 20A is a front surface of attachment portion 21, and second surface 20B is a rear surface of attachment portion 21. Attachment portion 21 has a thickness t1 (a first thickness), which is a maximum value of a thickness between first surface 20A and second surface 20B.

Attachment portion 21 has first surface 20A and second surface 20B in parallel from a bonding portion of attachment portion 21 and intermediate portion 23 to a position 21M. A thickness of attachment portion 21 from the bonding portion of attachment portion 21 and intermediate portion 23 to position 21M is thickness t1 and thus fixed.

Second surface 20B is inclined with respect to first surface 20A such that first surface 20A and second surface 20B approach each other from position 21M toward an edge 21T. Therefore, a thickness of attachment portion 21 from position 21M to edge 21T of attachment portion 21 decreases from position 21M toward edge 21T.

Attachment portion 21 has a portion 20 h for attachment to blade body 11 a. Portion 20 h is disposed between the bonding portion of attachment portion 21 and intermediate portion 23 and position 21M. Portion 20 h is located at a portion of attachment portion 21 having maximum thickness t1.

Portion 20 h for attachment to blade body 11 a is for example a through hole 20 h receiving bolt 11 b, as described above. Through hole 20 h penetrates through attachment portion 21 from first surface 20A to second surface 20B. Through hole 20 h has a diameter-expanded portion 20 ha expanding in diameter while extending from second surface 20B toward first surface 20A, and a radially fixed portion 20 hb extending from diameter-expanded portion 20 ha toward second surface 20B while maintaining a diameter. Diameter-expanded portion 20 ha is for example in the form of a truncated cone, and radially fixed portion 20 hb is for example in the form of a prism.

Wear portion 22 is located below attachment portion 21. Wear portion 22 has a first portion 22 a and a second portion 22 b. Second portion 22 b is located behind first portion 22 a.

First portion 22 a has a third surface 20C and a fourth surface 20D facing away from each other. Third surface 20C is a front surface of first portion 22 a, and fourth surface 20D is a rear surface of first portion 22 a. Third surface 20C is contiguous to first surface 20A.

First portion 22 a has a thickness t2 (a second thickness) between third surface 20C and fourth surface 20D. Thickness t2 is smaller than thickness t1 of attachment portion 21. A ratio of thickness t2 to thickness t1 (i.e., t2/t1) is 50% or less.

First portion 22 a has an edge 22T located on a side opposite to attachment portion 21. Third surface 20C and fourth surface 20D of first portion 22 a are in parallel. Thus, first portion 22 a extends from an end portion thereof closer to attachment portion 21 to edge 22T while maintaining thickness t2. Thickness t2 is fixed from edge 22T to a bonding portion of first portion 22 a and intermediate portion 23.

Second portion 22 b extends from a portion of fourth surface 20D of first portion 22 a toward a side opposite to third surface 20C. Second portion 22 b extends from edge 22T of first portion 22 a toward attachment portion 21 in the upward/downward direction (i.e., a direction along a shorter side of cutting edge 20). Second portion 22 b is in contact with fourth surface 20D of edge 22T. Second portion 22 b extends in the upward/downward direction from edge 22T to at least a portion at which first portion 22 a is connected to intermediate portion 23, and second portion 22 b is thus connected to first portion 22 a.

Second portion 22 b has a first end portion 22F connected to first portion 22 a on fourth surface 20D, and a second end portion 22R facing away from first end portion 22F. Second end portion 22R is located rearwardly of first end portion 22F.

Second end portion 22R of second portion 22 b has a portion located rearwardly of second surface 20B of attachment portion 21. Specifically, second end portion 22R of second portion 22 b at a base portion 22 b 2 is located rearwardly of second surface 20B of attachment portion 21. Second end portion 22R has a portion located on a side opposite to fourth surface 20D with respect to second surface 20B. Specifically, second end portion 22R at base portion 22 b 2 is located on a side opposite to fourth surface 20D with respect to second surface 20B. Thus, a total t4 in thickness of first portion 22 a and base portion 22 b 2 of second portion 22 b (see FIG. 6) is larger than thickness t1 of attachment portion 21 (FIG. 5).

Second portion 22 b has a tip portion 22 b 1 and base portion 22 b 2. Tip portion 22 b 1 is located below base portion 22 b 2. Tip portion 22 b 1 is a portion extending toward attachment portion 21 from edge 22T of first portion 22 a. Base portion 22 b 2 is a portion connected to tip portion 22 b 1 and located closer to attachment portion 21 than tip portion 22 b 1.

Second end portion 22R at tip portion 22 b 1 is inclined with respect to fourth surface 20D so as to approach fourth surface 20D as second end portion 22R approaches edge 22T. Second end portion 22R at base portion 22 b 2 is parallel to fourth surface 20D.

Intermediate portion 23 is located between attachment portion 21 and wear portion 22. Intermediate portion 23 has a fifth surface 20E and a sixth surface 20F facing away from each other. Fifth surface 20E is a front surface of intermediate portion 23, and sixth surface 20F is a rear surface of intermediate portion 23. Fifth surface 20E is contiguous to each of first surface 20A and third surface 20C.

Intermediate portion 23 has a thickness t3 (a third thickness) between fifth surface 20E and sixth surface 20F. Intermediate portion 23 has thickness t3 reduced from attachment portion 21 toward wear portion 22. Intermediate portion 23 has sixth surface 20F inclined with respect to fifth surface 20E so as to approach fifth surface 20E from attachment portion 21 toward wear portion 22. Intermediate portion 23 has sixth surface 20F so as to form a step between second surface 20B of attachment portion 21 and fourth surface 20D of wear portion 22.

Wear portion 22 has second portion 22 b connected to intermediate portion 23 at sixth surface 20F. Second portion 22 b is connected throughout sixth surface 20F in the upward/downward direction from a connecting portion between intermediate portion 23 and first portion 22 a to a connecting portion between intermediate portion 23 and attachment portion 21. Second portion 22 b reaches second surface 20B of attachment portion 21. Second portion 22 b is connected to a portion of second surface 20B.

First surface 20A of attachment portion 21, third surface 20C of first portion 22 a, and fifth surface 20E of intermediate portion 23 define a front surface FS of cutting edge 20.

As shown in FIG. 3, first surface 20A of attachment portion 21 and fifth surface 20E of intermediate portion 23 are continuously connected without making a break or a step. Fifth surface 20E of intermediate portion 23 and third surface 20C of first portion 22 a are continuously connected without making a break or a step. Thus, front surface FS composed of first surface 20A of attachment portion 21, fifth surface 20E of intermediate portion 23, and third surface 20C of first portion 22 a configure a single surface.

As shown in FIG. 4, cutting edge 20 has a plurality of second portions 22 b. The plurality of second portions 22 b are aligned in a longitudinal direction LD of cutting edge 20. The plurality of second portions 22 b are equally spaced in longitudinal direction LD of cutting edge 20. The plurality of second portions 22 b are disposed in parallel.

As shown in FIG. 5, front surface FS is curved in a cross section taken in the upward/downward direction from edge 21T of attachment portion 21 to edge 22T of first portion 22 a. In this cross section, a portion sandwiched between both edges 21T and 22T is recessed with respect to both edges 21T and 22T.

As shown in FIG. 6, second portion 22 b is a reinforcing rib for reinforcing first portion 22 a in strength. Total t4 in thickness of first portion 22 a and second portion 22 b is larger than thickness t2 of first portion 22 a.

Thickness t2 of first portion 22 a is equal to or smaller than a thickness of second portion 22 b (i.e., t4−t2). A ratio of thickness t2 of first portion 22 a to thickness (t4−t2) of second portion 22 b (i.e., t2/(t4−t2)) is 50% or less.

A pitch P of the plurality of second portions 22 b has a dimension for example of five times a width W of second portion 22 b.

Front surface FS extends linearly in the cross section taken in longitudinal direction LD shown in FIG. 6. First surface 20A of attachment portion 21, third surface 20C of first portion 22 a, and fifth surface 20E of intermediate portion 23 each extend linearly in the cross section taken in longitudinal direction LD shown in FIG. 6.

Effect

The present embodiment has an effect, as will be described below:

According to the present embodiment, as shown in FIG. 5, a second thickness t2 of first portion 22 a is smaller than a first thickness t1 of attachment portion 21. This helps first portion 22 a to dig into a target of excavation. Satisfactory performance for excavation can thus be provided.

The present inventors conducted a simulation of a phenomenon of excavation, and as a result have found that contact stress (=a wear rate) is hardly affected even when a contact area between cutting edge 20 and a target of excavation (e.g., the ground) is increased. Therefore, by reducing second thickness t2 of first portion 22 a, an area of contact with the target of excavation can be reduced, and excavation resistance (i.e., reaction force with respect to a fixed cut amount) can be reduced while a wear rate is held equally. This allows reduced force to be applied to press blade 11 against the target of excavation to excavate it, and thus improves fuel efficiency.

Further, as excavation resistance is reduced, blade 11 can be increased in width in the rightward/leftward direction when cutting edge 20 is pressed against the target of excavation with a given force. As a result, an increased amount of work and hence better performance for excavation can be achieved.

Further, second portion 22 b extends from a portion of fourth surface 20D of first portion 22 a toward a side opposite to third surface 20C. Second portion 22 b thus reinforces first portion 22 a in strength. This enhances cutting edge 20 in rigidity.

Further, second portion 22 b is also disposed at edge 22T of first portion 22 a. This allows cutting edge 20 to have an edge (i.e., edge 22T of first portion 22 a) enhanced in rigidity, and thus enhances cutting edge 20 in rigidity.

Furthermore, according to the present embodiment, it is unnecessary to attach a high-hardness bit to cutting edge 20 or add a wear-resistant alloy thereto. This allows cutting edge 20 to be manufactured with a reduced cost.

Further, in the present embodiment, as shown in FIG. 5, first portion 22 a has second thickness t2 fixed from edge 22T of first portion 22 a to an end portion of first portion 22 a located closer to attachment portion 21. Thus, even when first portion 22 a has edge 22T worn through excavation, performance for excavation equivalent to that when its use is started can be obtained. Further, as first portion 22 a has second thickness t2 fixed, resistance when cutting edge 20 digs into a target of excavation can be held low.

Further, in the present embodiment, as shown in FIG. 5, a ratio of second thickness t2 of first portion 22 a to first thickness t1 of attachment portion 21 (i.e., t2/t1) is 50% or less. First portion 22 a having thus reduced second thickness t2 allows further better performance for excavation.

Further, in the present embodiment, as shown in FIG. 5, intermediate portion 23 has thickness t3 reduced from attachment portion 21 toward wear portion 22. As intermediate portion 23 has thickness t3 thus gradually changed, there is no portion with abrupt variation in thickness. A portion with abrupt variation in thickness is likely to experience stress concentration during excavation, and is thus damageable. In the present embodiment, there is no such damageable portion.

Further, in the present embodiment, as shown in FIG. 5, second portion 22 b is a reinforcing rib. Thus, first portion 22 a is reinforced by second portion 22 b and thus enhanced in rigidity.

Further, in the present embodiment, as shown in FIG. 5, second portion 22 b reaches attachment portion 21. Second portion 22 b extending in the upward/downward direction throughout first portion 22 a having small thickness t2 can provide further enhanced rigidity.

Further, in the present embodiment, as shown in FIG. 5, second portion 22 b has second end portion 22R having a portion located on a side opposite to fourth surface 20D with respect to second surface 20B of attachment portion 21. Second portion 22 b can thus have a thickness (t4−t2) increased to provide further enhanced rigidity.

Further, if cutting edge 20 has front surface FS with unevenness in a cross section taken in longitudinal direction LD, cutting edge 20 is less likely to cause soil to flow in longitudinal direction LD thereof.

In the present embodiment, in contrast, as shown in FIG. 3, cutting edge 20 has front surface FS composed of a single surface (a curved face). Further, as shown in FIG. 6, cutting edge 20 has front surface FS linearly or in a single curved shape in a cross section taken in longitudinal direction LD. This facilitates ejecting soil and the like outside cutting edge 20 in longitudinal direction LD, and thus allows a land grading operation to be performed more efficiently.

Second Embodiment Configuration of Cutting Edge 20

Hereinafter, a configuration of a cutting edge in a second embodiment will be described with reference to FIGS. 7 to 10.

FIGS. 7 and 8 are a front perspective view and a rear perspective view, respectively, of a configuration of a cutting edge included in a work machine according to the second embodiment. FIGS. 9 and 10 are a cross section taken along a line IX-IX indicated in FIG. 8 and a cross section taken along a line X-X indicated in FIG. 8, respectively.

As shown in FIG. 7, cutting edge 20 of the present embodiment is different from the configuration of the first embodiment in that cutting edge 20 has front surface FS provided with a recess 20G.

A plurality of recesses 20G are aligned in longitudinal direction LD of cutting edge 20. The plurality of recesses 20G are provided at equal intervals for example. Each recess 20G extends from edge 22T of first portion 22 a toward edge 21T of attachment portion 21.

As shown in FIG. 8, recess 20G is defined by second portion 22 b. Second portion 22 b has an inclined portion 22 ba, a rear end portion 22 bb, and a pair of side portions 22 bc.

Paired side portion 22 bc each extend from a portion of fourth surface 20D of first portion 22 a toward a side opposite to third surface 20C. Paired side portions 22 bc are spaced from each other. Paired side portions 22 bc extend in parallel, for example.

Inclined portion 22 ba and rear end portion 22 bb are disposed so as to bridge paired side portions 22 bc. Paired side portion 22 bc each connect fourth surface 20D of first portion 22 a and a side end portion of inclined portion 22 ba. Further, paired side portions 22 bc each connect fourth surface 20D of first portion 22 a and a side end portion of rear end portion 22 bb.

As shown in FIG. 9, inclined portion 22 ba extends toward attachment portion 21 from a position corresponding to edge 22T of first portion 22 a. Inclined portion 22 ba is inclined with respect to front surface FS of cutting edge 20 so as to approach front surface FS of cutting edge 20 as inclined portion 22 ba approaches the position corresponding to edge 22T of first portion 22 a.

Rear end portion 22 bb is connected to an end portion of inclined portion 22 ba that is closer to attachment portion 21. Rear end portion 22 bb extends toward attachment portion 21 from the end portion of inclined portion 22 ba that is closer to attachment portion 21. Rear end portion 22 bb reaches attachment portion 21 beyond intermediate portion 23. Rear end portion 22 bb is connected to attachment portion 21. A portion of rear end portion 22 bb that extends toward attachment portion 21 from a portion of rear end portion 22 bb connected to inclined portion 22 ba extends parallel to front surface FS of cutting edge 20.

Inclined portion 22 ba and rear end portion 22 bb each have a front surface forming a bottom surface of recess 20G. Paired side portions 22 bc have their respective side surfaces to define those of recess 20G.

Second end portion 22R at rear end portion 22 bb on a side opposite to front surface FS is located farther from front surface FS than second surface 20B of attachment portion 21. A distance t4 from front surface FS to second end portion 22R at rear end portion 22 bb is larger than thickness t1 of attachment portion 21.

Note that the configuration of a cross section taken along line V-V indicated in FIG. 8 is the same as the configuration of the first embodiment shown in FIG. 5.

As shown in FIG. 10, side portion 22 bc of second portion 22 b functions as a reinforcing rib for reinforcing first portion 22 a in strength.

Distance t4 from front surface FS to second end portion 22R at rear end portion 22 bb is larger than a sum of thickness t2 of first portion 22 a and a thickness t5 of rear end portion 22 bb. Recess 20G has a depth D larger than thickness t2 of first portion 22 a.

Note that the configuration of cutting edge 20 of the present embodiment other than the above is substantially the same as that of the first embodiment, and accordingly, any component identical to that of the first embodiment is identically denoted and will not be described redundantly.

Effect

According to the present embodiment, as shown in FIG. 5, second thickness t2 of first portion 22 a is smaller than first thickness t1 of attachment portion 21. This, as well as the first embodiment, enables satisfactory performance for excavation and allows reduced force to be applied to press blade 11 against a target of excavation to excavate it.

Further, second portion 22 b has side portion 22 bc extending from a portion of fourth surface 20D of first portion 22 a toward a side opposite to third surface 20C. Side portion 22 bc reinforces first portion 22 a in strength. This enhances cutting edge 20 in rigidity.

Further, side portion 22 bc is also disposed at edge 22T of first portion 22 a. This allows cutting edge 20 to have an edge (i.e., edge 22T of first portion 22 a) enhanced in rigidity, and thus enhances cutting edge 20 in rigidity.

The presently disclosed embodiments are to be considered as illustrative in any respect and not restrictive. The scope of the present invention is not indicated by the above description but by the scope of the claims, and is intended to include meanings equivalent to the scope of the claims and any modifications within the scope.

REFERENCE SIGNS LIST

1 work implement, 2 body frame, 2F front end, 2 a rear frame, 2 aa engine compartment, 2 ab exterior cover, 2 b front frame, 3 cab, 4 front wheel, 5 rear wheel, 6 steering cylinder, 10 work machine (motor grader), 11 blade, 11 a blade body, 11 aa, FS front surface, 11 ab rear surface, 11 b bolt, 11 c nut, 11 d rail, 11 e holding frame, 11 f, 20 h through hole, 12 drawbar, 13 circle, 14, 15 lift cylinder, 16 drawbar shift cylinder, 17 blade shift cylinder, 18 hydraulic motor, 20 cutting edge, 20A first surface, 20B second surface, 20C third surface, 20D fourth surface, 20E fifth surface, 20F sixth surface, 20 h portion, 20 ha diameter-expanded portion, 20 hb radially fixed portion, 21 attachment portion, 21M intermediate position, 21T, 22T edge, 22 wear portion, 22F first end portion, 22R second end portion, 22 a first portion, 22 b second portion, 22 b 1 tip portion, 22 b 2 base portion, 22 ba inclined portion, 22 bb rear end portion, 22 bc side portion, 23 intermediate portion. 

1. A cutting edge for a work machine attached to the work machine, comprising: an attachment portion having a first surface and a second surface facing away from each other, and a first thickness being a maximum value of a thickness between the first surface and the second surface; and a wear portion integrated with the attachment portion, the wear portion having a first portion having a third surface contiguous to the first surface and a fourth surface facing away from the third surface, and having a second thickness between the third surface and the fourth surface, the second thickness being smaller than the first thickness, and an edge located opposite to the attachment portion, and a second portion extending from a portion of the fourth surface of the first portion toward a side opposite to the third surface, and extending from the edge of the first portion toward the attachment portion.
 2. The cutting edge for a work machine according to claim 1, wherein the attachment portion has a through hole, and the through hole has a diameter-expanded portion connected to the first surface.
 3. The cutting edge for a work machine according to claim 1, wherein the second thickness is fixed from the edge of the first portion to an end of the first portion located closer to the attachment portion.
 4. The cutting edge for a work machine according to claim 1, wherein a ratio of the second thickness to the first thickness is 50% or less.
 5. The cutting edge for a work machine according to claim 1, further comprising an intermediate portion located between the attachment portion and the wear portion, wherein the intermediate portion has a thickness decreasing from the attachment portion toward the wear portion.
 6. The cutting edge for a work machine according to claim 1, wherein the second portion is a reinforcing rib.
 7. The cutting edge for a work machine according to claim 1, wherein the second portion configures a recess recessed toward the fourth surface of the first portion with respect to the third surface of the first portion.
 8. The cutting edge for a work machine according to claim 1, wherein the second portion reaches the attachment portion.
 9. The cutting edge for a work machine according to claim 1, wherein the second portion has a first end portion connected to the fourth surface and a second end portion opposite to the first end portion, and the second end portion has a portion located opposite to the fourth surface with respect to the second surface of the attachment portion.
 10. A blade for a work machine comprising: the cutting edge for the work machine according to claim 1; and a blade body to which the cutting edge is attached.
 11. A work machine comprising: the blade for the work machine according to claim 10; and a body of the work machine to which the blade for the work machine is attached. 